Method and apparatus for processing fluids

ABSTRACT

The present invention relates generally to the processing of fluids and/or their carriers. Carriers may comprise pipes, tubes and the like or reservoirs for the distribution and/or storage of fluids. In one form, the present invention relates to a method and apparatus that is suitable for use in the treatment of various fluids, such as water, by introducing at least one chemically active metal into the water and its carriers for disinfection of the water in a controlled manner. The invention also relates to a biasing means for displacement of an electrode arrangement to allow for the introduction of ions into a fluid at a controlled or easily monitored rate that is commensurate with the amount of fluid flow.

FIELD OF INVENTION

The present invention relates generally to the processing of fluidsand/or their carriers. Carriers may comprise pipes, tubes and the likeor reservoirs for the distribution and/or storage of fluids. Inparticular, the present invention relates to a method and apparatus thatis suitable for use in the treatment of water by introducing at leastone chemically active metal, for example, antimicrobial forms of metalinto the water and its carriers for disinfection of the water in acontrolled manner, and it will be convenient to hereinafter describe theinvention in relation to that application. It should be appreciated,however, that the present invention is not limited to that application,only. Notably, the present invention is suitable for use in theprocessing of other fluids, for example, milk, starches, syrups, fruitjuices, biological fluids from animals or humans, liquid fossil fuelsand the like. In one particular aspect the present Invention is alsosuitable for use as a method and means for fluid flow recognition ordetermination.

BACKGROUND OF INVENTION

In the context of the present invention, it is to be taken that the term“fluid” applies to any material that displays liquid-like or gas-likebehaviour or physical properties.

The treatment of fluids by disinfection, for example, is an importantprocess enabling the safe and efficient use and/or consumption of thesefluids in industrial and domestic environments. For example, the abilityto disinfect water for general consumption by animals and/or humansincluding drinking and recreational use is paramount. An exampleapplication of such treated water includes production liquid for thepreservation of fresh cut flowers. When treating fluids it is alsocritical that the flow of the given fluid is determined and/orcontrolled.

Prior art techniques used for disinfecting fluids, such as for examplein Australian Patent 53032/98 (735166), Australian Patent 11859/97(702918) and Australian Patent 24394/95 (685630), make use of theability of silver ions to effectively destroy micro-organisms such asbacteria and viruses. However, in these prior art systems, the silverthat is being introduced into a given fluid requires sophisticatedelectronic equipment for either monitoring the amount or dose of silverbeing introduced or monitoring the volumetric flow of fluid to betreated. Moreover, regulatory authorities throughout the world nowstipulate their own varying individual maximum levels of silver that maybe added to fluids for their treatment These various regulations make itdifficult and expensive to control the amount of silver to be releasedinto a given flow of fluid.

Other prior art systems, such as disclosed in DE 4107708, attempt toaccurately monitor fluid flow. These systems require the use of delicateon/off flow switches and are therefore, expensive. Generally, the flowswitches of prior art systems are made using glass encased reed switchesand magnets of differing types. Reed switches, in particular, are easilycracked and as a result may fail to perform. Furthermore, the circuitsrequired to control these systems often fail especially where corrosionoccurs as would be expected when placed in close proximity or contactwith the various fluids being treated. In the event of these failures,the prior art systems cannot provide for regulated introduction ofsilver into a fluid.

Prior art silver disinfection systems may also have a tendency to causean overdose of silver into the fluid. Notwithstanding the toxic effectsof excessive silver consumption, a further problem associated withsilver overdosing has been shown, namely, de-oxygenation. When excessiveamounts of silver are introduced into a body of fluid the excess silverwill absorb the available free oxygen and may use the absorbed oxygen todestroy anaerobic micro-organisms by the process of oxidation leavingthe fluid in a de-oxygenated form. The de-oxygenated fluid then becomesan environment that is conducive to the multiplication and resultantre-infection of micro-organisms. This re-infection is also assisted bythe fact that dissolved silver will, in a relatively short time, plateout to the walls containing the fluid or, being heavy will fall out ofsuspension removing the active silver from the fluid. Thus, there is aneed to maintain a correct balance of silver concentration forsuccessful disinfection.

Prior art systems such as that disclosed in Australian Patent 53032/98(735166) have provided a solution to the problem of plating by producingsuspended silver particles instead of silver ions. Such particles arenot soluble and cannot plate out and, in turn, as the particles are ofpure silver and not silver ions forming silver salts, they may notproduce toxic effects in high doses. However, complex circuits arerequired to produce pure sliver particles and this is a disadvantage,particularly when a readily useful and easily accessible means ofdisinfection is required in the market. Furthermore, the lack of platingdisplayed by silver particles is a disadvantage when it is desirable totreat the surface or walls of a fluid carrier to produce, for example, abacteriostatic coating of silver preventing biofilm build up.

It is therefore an object of the present invention to provide a methodand apparatus, which ameliorates at least one disadvantage of the priorart arrangements. It is also an object of the present invention toprovide a method and apparatus providing for the control or monitoringof the introduction of chemically active forms of metal into a fluidthat may flow at a variable rate. It is also an object of the presentinvention to provide a method and apparatus for providing control overthe plating out effect of an introduced metal on the walls of a fluidcarrier.

Any discussion of documents, devices, acts or knowledge in thisspecification is included to explain the context of the invention. Itshould not be taken as an admission that any of the material formed partof the prior art base or the common general knowledge in the relevantart on or before the priority date of the claims herein.

SUMMARY OF INVENTION

In one aspect the present invention provides an apparatus for processingfluid comprising a body defining a fluid flow passage having a fluidinlet and a fluid outlet, the body comprising a first electrodearrangement and a second electrode arrangement displaceable with respectto the first electrode arrangement, the first and second electrodearrangements adapted for connection to a supply of electric current suchthat fluid within the body forms part of an electrolytic cell providingfor a flow of ions between the first and second electrode arrangements;biasing means operatively associated with the second electrodearrangement and adapted to displace the second electrode arrangementagainst a flow of fluid within the body in order to displace the secondelectrode arrangement into closer proximity with the first electrodearrangement as the fluid flow rate increases, thereby increasing theflow of ions, and to displace the second electrode arrangement away fromthe first electrode arrangement as the fluid flow rate decreases,thereby decreasing the flow of ions.

In accordance with another aspect of the present invention, there isprovided a method of processing a fluid comprising the steps ofproviding a body defining a fluid flow passage having a fluid inlet anda fluid outlet, the body comprising a first electrode arrangement and asecond electrode arrangement displaceable with respect to the firstelectrode arrangement, the first and second electrode arrangementsadapted for connection to a supply of electric current such that fluidwithin the body forms part of an electrolytic cell providing for a flowof ions between the first and second electrode arrangements; providingan electric current supply from an electric circuit to the first andsecond electrode arrangements; passing the fluid through the body suchthat the displacement of the second electrode arrangement is biasedagainst the flow of fluid within the body in order to displace thesecond electrode arrangement into closer proximity with the firstelectrode arrangement as the fluid flow rate increases, therebyincreasing the flow of ions, and to displace the second electrodearrangement away from the first electrode arrangement as the fluid flowrate decreases, thereby decreasing the flow of ions.

A further aspect of the present invention provides a method ofdetermining fluid flow comprising the steps of providing a body defininga fluid flow passage having a fluid inlet and a fluid outlet, the bodycomprising a first electrode arrangement and a second electrodearrangement displaceable with respect to the first electrodearrangement, the first and second electrode arrangements adapted forconnection to a supply of electric current such that fluid within thebody forms part of an electrolytic cell providing for a flow of ionsbetween the first and second electrode arrangements; providing anelectric current supply from an electric circuit to the first and secondelectrode arrangements; passing the fluid through the body such that thedisplacement of the second electrode arrangement is biased against aflow of fluid within the body in order to displace the second electrodearrangement into closer proximity with the first electrode arrangementas the fluid flow rate increases, thereby increasing the flow of ionsand to displace the second electrode arrangement away from the firstelectrode arrangement as the fluid flow rate decreases, therebydecreasing the flow of ions; determining the fluid flow rate bymeasuring either one or both of an ion current density between the firstand second electrode arrangements, and a relative displacement of thefirst and second electrode arrangement.

The present invention still further provides biasing means adapted forcontrolled operation by the passage of fluid in a fluid passage, thebiasing means being operative to displace a first electrode relative toa second electrode, the biasing means comprising a displacement meansfor displacing the first electrode toward the second electrodeproportional to an increase in the rate of flow of fluid in the passage.

The present invention also provides a trigger means operably associatedwith a biasing means as disclosed herein, the trigger means comprising afirst switch means disposed in association with the displacement means,a second switch means adapted to cooperate with the first switch means,in a first position, to form a trigger.

The present invention also provides a trigger means operably associatedwith an apparatus as disclosed herein, the trigger means comprising afirst switch means disposed in association with the second electrodearrangement, a second switch means adapted to cooperate with the firstswitch means, in a first position, to form a trigger.

In essence, the present invention stems from the realisation thattransducing or converting fluid flow to a biased displacement of atleast one electrode arrangement of an electrolytic cell provides a flowof ions, or an ion current density, within the fluid and betweenelectrode arrangements, which corresponds to and is therefore regulatedby the flow rate of the fluid. This biased displacement of an electrodearrangement allows for the introduction of ions into a fluid at acontrolled or easily monitored rate that is commensurate with the amountof fluid flow. Further, it has been found that, correspondingly, ameasurement of the relative displacement of the first and secondelectrode arrangements and/or the ion current density or rate of ionintroduction into the fluid provides a corresponding determination ofthe fluid flow rate itself. Within an electrolytic cell, forming part ofthe apparatus in accordance with one embodiment of the presentinvention, an electric voltage applied between the first and secondelectrode arrangements will provide a flow of ions within the fluid andbetween the first and second electrode arrangements that increases withincreasing fluid flow rate as the second electrode arrangement movesinto closer proximity to the first electrode arrangement and decreaseswith decreasing fluid flow rate as the second electrode arrangementmoves away from the first electrode arrangement.

In preferred embodiments of the method and apparatus for processing afluid according to the present invention, the rate of introduction ofions into a fluid may be such that the ion flow or ion current densitywithin the processed fluid is regulated in a directly proportionalrelationship to the fluid flow rate. Further to this, in preferredembodiments, the present invention may provide a directly proportionalrelationship between the displacement of the electrode arrangements andthe fluid flow rate.

In accordance math a preferred embodiment, the first electrodearrangement comprises an electrode fixed relative to the body and thesecond electrode arrangement comprises two opposed electrodes, mountedwithin a moveable support, allowing for positioning of the fixedelectrode therebetween and wherein, the biasing means comprises a springconnected to the body means. The moveable support may be a pistonarrangement comprising a sliding piston. Alternatively, the secondelectrode may be fixed relative to the first electrode, with the firstelectrode being moveable. Again, alternatively both electrode may bemoveable relative to the body and/or relative to each other.

The ions produced by the fluid processing apparatus may be metal ionsemanating from the electrode arrangements during electrolysis and havinganti-microbial and plating out properties such that the metal Ions plateto fluid contact surfaces of the body. Furthermore, these ions may plateto contact surfaces of a fluid carrier means located or connected beyondthe body to form a biostatic film on a number of fluid contact surfaces.

The electrodes may be comprise one or more different metals.Alternatively, each electrode may be made of a different metal, orproduce ions of different metals.

Preferably, at least one of the electrode arrangements may comprisesilver for producing a flow of silver ions between the electrodes. Anysuitable electric circuit may be used for supplying electric current tothe electrolytic cell formed within the apparatus in accordance withpreferred embodiments of the invention.

In one preferred embodiment, the apparatus of the present invention mayfurther comprise: fluid flow measurement means for determining whetherthere is actual fluid flow between the inlet and the outlet of the body,and; an electric circuit for supplying electric current to theelectrolytic cell may comprise circuit control means for reducing theelectric current supplied to the first and second electrode arrangementsif there is no actual fluid flow determined by the fluid flowmeasurement means. The fluid flow measurement means may comprise a flowswitch having a magnet and a reed switch.

The electric circuit may be arranged to comprise circuitry foractivating a standby mode. It is also possible for the electric circuitto further comprise circuitry for activating an operating mode. Circuitmeans may be included for increasing an electric current supply to thefirst and second electrode arrangements in response to a fluid flowcondition.

The fluid processing apparatus may further comprise fluid flowdetermination means comprising an ion current measurement arrangementfor measuring the ion current density between the first and secondelectrode arrangements where the ion current density corresponds to thefluid flow rate. Alternatively, a measurement of the relativedisplacement of the first and second electrode arrangements may providea determination of the relative fluid flow rate. In further embodimentsthe fluid processing apparatus may be calibrated such that the relativedisplacement of the first and second electrode arrangements provides adetermination of the absolute volumetric fluid flow rate.

Either analogue or digital circuit means may be utilised for reducingthe electric current supplied to the first and second electrode means ifthere is no actual fluid flow determined by the fluid flow measurementmeans. Moreover, as a preferred alternative to the use of flow switchmeans for measuring actual fluid flow to activate and deactivate theprocessing apparatus, the electric circuit means in accordance withpreferred embodiments of the present invention may comprise circuitryfor activating the standby mode and operating mode as mentioned above.

A display may be provided to indicate the activation of the standby modeand/or the activation of the operating mode,

Other aspects and preferred aspects are disclosed in the specificationand/or defined in the appended claims, forming a part of the descriptionof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of one or more preferred embodiments ofthe present invention will be readily apparent to one of ordinary skillin the art from the following written description with reference to and,used in conjunction with, the accompanying drawings, in which:

FIG. 1 is a diagrammatic sectional side elevation of a fluid processingapparatus according to a preferred embodiment of the present inventionand suitable for use in performing the method of the present invention;

FIG. 2 is a circuit diagram illustrating, in part, an electric circuitaccording to a preferred embodiment of the present invention;

FIGS. 3 a, 3 b and 3 c illustrate alternative electrode configurationsin accordance with a further embodiment of the present invention;

FIG. 4 illustrates a fluid processing apparatus according to a preferredembodiment of the present invention operational in an increased fluidflow situation; and

FIG. 5 illustrates an adjustable reed switch and magnetic triggerconfigured in accordance with a further embodiment of the presentinvention.

DESCRIPTION OF PREFERRED EMBODIMENT

An exemplary embodiment of the present invention resides in its use forthe processing of a fluid by means of silver ion disinfection for thedisinfection of a flowing fluid in conjunction with making use of thebenefit of the plating out properties of silver ions to the surface of afluid carrier comprising, for example, a body in the form of a chamberfor fluid flow.

Referring to FIG. 1, a fluid processing unit is shown generally as 1.The fluid processing unit 1 may be an ion disinfection apparatus orequally, a fluid flow determination apparatus and is defined by a bodyhaving a chamber 2 formed with a spaced inlet 3 and an outlet 4respectively at opposite ends of the chamber 2. The outlet 4, orpossibly more than one outlet, may be situated so as to breach the wallof chamber 2 whereby the fluid may be caused to flow from inlet 3 tooutlet 4. Within the unit 1 shown in FIG. 1, the first electrodearrangement comprises a single silver electrode 6 and the secondelectrode arrangement comprises two silver joined electrodes 5. Theelectrodes are shown as rods or bars, however, they may be of anysuitable shape or a combination of shapes. For example, one, a part ofone or each of the electrodes may be a hollow tube as illustrated inFIG. 3 a, a mesh or grid-like configuration as illustrated in FIG. 3 b,and/or a helical-like or ring-like configuration as illustrated in FIG.3 c. The Joined electrodes 5 are mounted moveably by virtue of housingor support 11 adjacent the inlet opening 3. In the embodiment shown, thehousing is a piston-like structure, having apertures selected accordingto the fluid type which passes through the chamber 2. The size of thepiston or apertures can be selected or varied as required according tothe type of fluid passing through the chamber. In other words, if thefluid is relatively viscous, a smaller piston and/or larger apertures ormore apertures may be provided, whereas if the fluid has less viscosity,a larger, more tightly fitting piston and/or smaller or reduced numberof apertures may be used. Not only can the piston size vary, theaperture size (where fluid flows into the chamber) and/or the sizeand/or tension of the spring may also vary.

The assembly of joined electrodes 5 is biased by a biasing means 7 and8, such as light stainless steel tension spring or other suitablebiasing means 7 held by an anchor 8, operatively associated with ahousing or support 11 for the electrodes 5 to occupy a, position inwhich the assembly retracts from an electrolysing position in the caseof fluid flow to a position remote from electrode 6 when the flow offluid reduces or ceases. Assembly 11 is adapted to be moved, by the flowof fluid, against the action of the spring 7 by incoming fluid so thatthe fluid will enter and pass through the chamber 2. As illustrated, theparts are made and arranged such that movement or displacement of theelectrode assembly 5 against the action of the spring 7 will cause anormally greater distance between electrode assembly 5 and electrode 6,which is in a normally fixed position, to decrease. It would berecognised by the person skilled in the art that the portion of thechamber 2 comprising the electrode assembly 5, stationary electrode 6and the fluid therebetween forms an electrolytic cell. It would also berecognised by a person skilled in the art that the relative movement ofthe electrode is important, not necessarily which electrode moves or isstationery. For example, an arrangement may be envisaged where electrode5 may be made to be stationery, and electrode 6 may be mounted in amoveable manner.

The circuit 20 of FIG. 2 will detect an increase in electron flow withinits wired circuit path as the distance between electrode assembly 5 andelectrode 6 decreases and once the electron flow exceeds preferably 2milliamps, the circuit 20 of FIG. 2 will apply a potential differencebetween electrode assembly 5 and electrode 6. Electrode assembly 5 willbe displaced so that a force due to the flow of the fluid is balanced bya force due to the tension in the spring 7. At a given potentialdifference, as electrode assembly 5 is displaced toward electrode 6, thecurrent flowing between the electrodes increases due to the reducedresistance between the electrodes of 5 and 6. This in turn translates toa greater silver ion production or ion current density increasing inconcentration as the increase in flow of the fluid causes the moveableelectrode assembly 5 to lessen the distance between electrodearrangements 5 and 6. As the fluid flow decreases, the distance betweenthe electrodes of assembly 5 and electrode 6 becomes greater lesseningthe amount of silver production from the electrodes and corresponding toa decreased ion current density. The electrical supply to theaforementioned moveable electrodes 5 may be connected to a spring anchor8 via electrode lead 10. The electrical supply may correspondingly alsobe connected to electrode 6 directly from electrode lead 9. It would berecognised by the person skilled in the art that measurement of the ioncurrent density between electrodes 5 and 6 provides a correspondingmeasurement of the fluid flow rate under these conditions. Equally, itwould be recognised that the anchor 8 and spring 7 need not beconductive, if the electrical connection 10 is made directly to theelectrode 5, perhaps via an electrical connection, wired or otherwise(not shown) directly to the electrode 5.

Electrode assembly housing or support 11 is substantially cylindricaland provided with a guided displacement means and has a clearance withinchamber 2. The aforementioned light tension spring 7 may be anchored byanchor 8 which is of non-electrolysing but conductive metal element,preferably, grade 316 stainless steel. Once fluid enters chamber 2 viainlet 3 and tension is applied to spring 7 an electrical contact is madevia spring 7 from anchor 8 to electrodes in electrode assembly 5. Astandby pulse as described in more detail below from the circuit 20 ofFIG. 2 may check for any ion current flow between electrodes of assembly5 and electrode 6 preferably every two to five seconds. Once a currentflow of preferably 2 milliamps is present, then the circuit 20 of FIG. 2applies a current flow between the electrodes 5 and 6. When electrodeassembly 5 is at a normally standby position (without a flow of fluid)the current flow between electrodes 5 and 6 will be less than 2milliamps and the circuit 20 of FIG. 2 will prevent any current fromflowing between said electrodes by acting as a gate. At this stage ofoperation, the circuit 20 of FIG. 2 may commence a test pulse preferablyevery two to five seconds to monitor the activity of the apparatus.

The method of operation of the apparatus and the apparatus itselfcomprising the normal operating and standby mode is now described infurther detail in accordance with a preferred embodiment of theinvention, which provides a method and apparatus for silver iondisinfection of water with reference to the accompanying drawings. Thewater disinfection apparatus of FIG. 1 provides a body or chamber 2defining a fluid flow passage formed between inlet 3 and outlet 4. Aminimum of one electrode 6 is mounted stationary with respect to thechamber 2 for the flow of water to pass over it in its passage from theinlet opening 3 to the outlet opening 4. A minimum of one and preferablytwo electrodes 5 are mounted to or supported by a displaceable ormoveable housing, preferably a sliding piston 11, arranged so that itsouter end has the electrodes 5 exposed. One or all of the electrodes 5,6 are preferably made of silver. Of course, other electrodes may be usedwhere a specific type of ion is required to be dispersed into the fluid.

In FIGS. 1 and 4, a path travelled by the fluid flowing is indicated bydotted lines. Fluid enters the chamber 2 at inlet 3. The fluid passesthe biasing means, anchor 8 and spring 7. The fluid passes through thesliding piston 11 and passes over or proximate the exposed electrodes 5.As the flow of fluid increases, the fluid enters the chamber 2 via inlet3 and provides a force against housing 11. The housing via its piston 11moves (as well as the two attached exposed electrodes 5) in a directionA towards and in closer proximity to the aforementioned stationaryelectrode 6. A DC power supply having terminals denoted by T1 and T2 inFIG. 2, is connected via the circuit 20 of FIG. 2, to the electrodes 5and 6 for the production of ions via electrolysis. The fluid passes theelectrodes 5 and 6 and exits via outlet 4. As shown in FIG. 1, little orno fluid flow passes region 13.

The circuit 20 of FIG. 2 is coupled to the electrodes 5 and 6 and mayact as a gate to prevent current leakages of less than around 2milliamps from activating the production of silver ions. The samecircuit 20 makes a current above around 2 milliamps available to theelectrodes 5 and 6 and may incorporate a reversing polarity for thecleaning of the electrodes 5 and 6.

As the piston 11 holding the two electrodes 5 is moved towards the fixedor stationary electrode 6, a current draw above 2 milliamps is createdallowing the activation of electrolysis hence producing silver ions. Thecloser the piston 11 is moved toward the fixed electrode 6 by thegreater flow of water, the greater the current draw and hence, thegreater amount of silver ions produced. In order to enable this largerfluid flow to pass through the chamber 2, frusto-conical or othersuitably shaped recesses 12 are provided.

Referring to FIG. 4, the housing 11 and its associated electrode 5 isshown displaced more closely toward the electrode 6 than that shown inFIG. 1. This is the situation caused by increased fluid flow through thechamber 2. It can be seen spring 7 is more extended than as shown inFIG. 1, and that a gap 13 has enlarged or emerged to assist in allowingthe increased fluid flow to pass through the chamber 2. The fluidpassing gap 13 and passing the electrodes 5 and 6 is converged or mixedas it passes the outlet 4.

Again, the fluid path is indicated by way of a dotted line. The fluidflow passes into the chamber 2 via inlet 3. The fluid then passes piston11, and a portion passes into and around electrode 5, whereas anotherportion passes through gap 13. The fluid also passes electrode 6 andexits via outlet 4.

The type and rate of ions being produced has been predeterminedaccording to the kind of electrodes used and the type of fluid passingthrough the chamber 2, respectively.

Alternatively, any one or a combination of a number of adjustments maybe made to the chamber or it components in order to set or regulate thequantity of ion production for a given fluid flow. For example:

-   the spring tension may be adjusted, thereby adjusting the    displacement of the electrodes relative to each other;-   the electrical supply or circuit 20 may be appropriately adjusted to    provide more or less ion production by increasing or decreasing the    electrical energy supplied to the electrodes;-   alternative electrodes, such as titanium electrodes may be provided    for use as stable electrodes in fluid flow measurement, or a    combination of titanium and other metals that easily produce ions,    for example, Magnesium, Copper, Zinc, Silver;-   a number of electrodes may be provided in the chamber enabling a    selection or combination of electrodes to be activated thus    providing a selection or combination of ions being provided into the    fluid;-   the gap 13 may be adjusted by means of a screw or other displacement    means to either increase the gap (thus decreasing the force as    applied to the housing 11 by the inlet fluid and thus decreasing the    movement of the housing and electrode 5 relatively to electrode 6)    or to decrease the gap (thus increasing the force applied to housing    11 by the inlet fluid and thus increasing the displacement of    electrode 5 toward electrode 6) and increasing the production of    ions;-   the housing 11 may be adjustable and either expanded or contracted    within the chamber, thus restricting or increasing fluid flow past    the housing.

As the piston 11 holding the two electrodes 5, which may be fixed to astainless steel spring 7, retracts due to the loss of water flow, thegap 13 will decrease, the current draw is less and thus produces alesser amount of silver ions. The ion flow may be in direct proportionto the fluid flow rate. However, there is a direct relationship betweenion flow and the conductivity of the fluid. For example, more ions insalt water and less ions in tap water. Equally, the rate of ionproduction may be predetermined in accordance with the type of fluid orenvironment of use of the present invention. In this way, the presentinvention provides a relatively steady concentration, or a proportionalamount, of ions to the fluid as it passes through the chamber 2. Anyother desired circuit for the production of metal particles other thansilver and, which have anti microbial properties, may be fitted afterthe aforementioned controllable gate circuit 20.

The present invention may also involve electrolysis being activated ordeactivated using a magnet and reed switch. The activation and/ordeactivation of electrolysis may be provided by any suitable flow switchthat is available in the market place such as those comprising a magnetand reed switch. FIG. 5 illustrates one embodiment of the presentinvention incorporating an improved adaptation of such a configuration.The chamber 2 has an inlet 3 and outlet 4 for fluid ingress and egress,respectively. Electrodes 6 and 5 are provided. Housing 11 provides amechanism by which electrode 5 can be displaced either toward or awayfrom electrode 6. Suitable biasing means (not shown) are also providedfor the housing. A fluid pathway 16 is provided through which fluid canpass the housing 11 and circulate proximate the electrodes 5 and 6 andexit via outlet 4. In accordance with this aspect of invention, a magnet14 is provided in housing 11. A reed switch 15 is provided on anadjustable mounting 17, and which can be held fixed permanently ortemporarily by locking means 18. In accordance with this aspect ofinvention, the reed switch 15 can be moved in direction B to a positionwhere the magnet force of magnet 14 closes or opens the reed switch oncethe housing 11 has moved a predetermined amount. In other words, giventhat the housing 11 moves in direction B dependent on the fluid flow,the reed switch 15 can also be moved to a position where it is requiredthat the switch close or open (by virtue of the magnetic force of magnet14 acting on the switch elements 21 internal of the reed switch). Oncethe internal reed switch elements 21 are acted upon by the magnet force,corresponding electrical connects 19 and 20 can be made to externalcircuitry, such as that of FIG. 2 to supply electrical power to theelectrodes 5 and 6.

In using this aspect of invention, for example when there is no fluidflow through the chamber, the reed switch 15 may be moved to a positionwhere the magnetic force of magnet 14 closes the reed switch. Thus whenthere is no fluid flow, the reed switch elements 21 are closed. In suchan arrangement, when fluid is passed through the chamber 2, the housing11 (and it's associated magnet 14) move toward electrode 6 as describedabove. This movement may cause reed switch elements 21 to be no longerin a closed position due to the magnetic force of magnet 14, and thusthe reed switch 15 will provide an indication of when fluid flow isoccurring in the chamber 2. This indication may be used to trigger anelectrical circuit (not shown) to supply electrical power to theelectrodes 5 and 6. Conversely, the reed switch 15 may be movedproximate the magnet 14 so as the internal elements 21 remain in an opencircuit position until the housing 11 moves and the magnetic force ofmagnet 14 closes the internal elements 21. This closing mayalternatively be used as an indication of fluid flow and the need tosupply electrical power to the electrodes.

In a preferred embodiment of the present invention when a flow switch isnot used to activate or deactivate electrolysis, the electronic circuit20 of FIG. 2 may be utilised to determine water flow activity. Thisfeature of the present invention allows for fully automatic operationunder micro-control. The amount of silver electrolysed into the water isa function of both the current density of the water and the water flowrate. The current density regulating method of the present invention isable to accurately maintain the correct levels of electrolysed silver inthe water to be treated under varying flow rates and conditions and, inaccordance with a preferred embodiment, is able to activate ordeactivate the electrolysing process under no flow conditions. Notpertaining to reed switches or other flow switches the operation of thecircuit 20 that provides an alternative to the activation anddeactivation of electrolysis for the present invention is described asfollows with reference to FIG. 2.

The circuit 20, acting as a gate, is supplied with regulated DC voltageacross power supply input terminals T1 and T2. Circuit element D1provides reverse polarity protection for the circuit 20 and capacitor C1provides filtering from noise and transients. Integrated circuit U3 andcapacitor C2 provide the microprocessor U1 with a regulated 5V DC supplysource. Variable resistor R1 provides an adjustable voltage input to thepositive input of operational amplifier U2-A. Operation amplifier U2-Ais configured as a unity gain buffer with transistor Q2 inside of thefeedback loop. Capacitor C3 provides a power supply bypass foroperational amplifier U2-A and capacitor C4 provides a bypass for thecollector transistor Q2. Transistor Q2 is configured as voltage followerand provides the necessary positive current to electrolyse the silverthrough terminal T3 via blocking diode D4.

Resistor R5 provides a resistive load to the emitter of Q2 to ensure thecircuit will perform properly regardless of whether there is a loadpresent or not at T3. Blocking diode D4 ensures that any galvanicvoltage created by the water processing unit 1 does not result in anysubstantial current flow through the unit 1. Without the blocking diodeD4 the internally generated galvanic voltage of the unit 1 will continueto electrolyse the silver into the water, potentially above safe levelsduring long periods of no water flow.

The current return path of circuit 20 consists of terminal T4 andcurrent shunt resistor R6 the other end of which is connected to circuitground. Capacitor C5 provides filtering for any high frequency AC noisecomponents. Operational amplifier U2-B is configured as a non-invertingvariable gain amplifier. The feed back loop comprises resistors R9, R8and R7. Resistor R8 is a potentiometer and enables the circuit 20 andthus the water processing unit 1 overall to be calibrated for theselected operating set point. The amplified current sense voltage isfiltered by the RC low pass filter network consisting of R10 and C6 andis applied to an analogue to digital converter input of themicroprocessor U1 at pin 7 thereof, as illustrated in FIG. 2. Thecircuit 20 is calibrated by adjusting R1 to give the desired currentflow at the maximum water flow rate. The current threshold level iscalibrated with resistor R8. The current threshold value is selected tobe nominally higher than the current drawn by the unit 1 in the no fluidflow condition. Under normal operating conditions the circuit 20 appliesthe full current source voltage to the unit 1 and the current ismodulated relative to the rate of water flow through the unit 1 by meansof the water flow rate modulating the relative displacement of theelectrodes, as has been previously described. When the water flowthrough the unit 1 is terminated the current will fall below the lowcurrent threshold programmed into microprocessor U1 which thenincrements an internal timer as long as the current is below the lowcurrent threshold. The micro processor U1 continually checks the amountof time that the current has been below the low current threshold andwhen the predetermined amount of time has been accumulated activatestransistor Q1 which effectively shunts the output of voltage dividerresistor R1 to ground effectively reducing the current flowing throughthe unit 1 to zero to effect a standby mode. The timer measures acontinuous time period of current being below the predeterminedthreshold value to activate the standby mode and will reset the timer tozero should normal system current levels be detected before thepredetermined threshold low current time is accumulated. While the unit1 is in the standby mode controllable circuit 20 samples the unit 1 forfifty milliseconds every five seconds to sense if the current has againincreased indicating that water flow through the unit 1 has beenresumed. The threshold to indicate the unit 1 is again in active use ornormal operating mode is purposely made higher by a small amount toprovide some hysteresis in the function of the device to ensure that itdoes not reach a threshold condition where it would toggle continuallybetween the two operating states. The sampling method results in a dutycycle of one percent, which would allow for normal periods of non usewith complete confidence that the silver levels in the water would notrise above generally accepted or regulated safe levels. The controllablecircuit 20 is equipped with red LED D2 powered through current limitingresistor R3 from the microprocessor U1 and a green LED D3 poweredthrough current limiting resistor R4 from the microprocessor U1 toprovide a visual indication to the user of whether the unit is in thestandby or operating mode.

A further embodiment is contemplated in respect of the presentinvention, particularly for application to gases, but may be adapted foruse with fluids in general.

With regard to use of the present invention with gases, ion productionwill occur for those gases that can produce a resistance between theelectrodes. Thus, for these gases ions are introduced into the flow orequally measurement of flow can be deduced in this case. For gases thatdo not produce resistance between the electrodes, then ion introductionwon't occur but they can be used for fluid flow measurement. In the usewith gases, it is considered that the embodiment needs to “reconfigure”the electrodes only in as much as they are very near or touching toproduce the required electrolysis.

Alternatively with regard to gases, disinfectant silver can be producedin solution as per the normal liquid case disclosed above. This silvercolloid solution may then be vaporised downstream in another chamberremoving the liquid and leaving the silver particles to be mixed in witha given gas. This produces a liquid with the desired form of silver,namely colloid, as well as a given gas also having silver particles foruse in an airborne form of treatment of the ambient environment. Forexample, silver of a first form can be produced, introduced into theliquid, then have the liquid treated downstream further (for example byvaporising the liquid), leaving the first form of the silver. This firstform of silver can then be added to a gas, to provide, for example, an‘aerosol form’ or atomising form of silver.

Furthermore, with regard to gases, in another alternative, the device ofthe present invention can be calibrated with a standard liquid andhaving done this the desired gas can be introduced into the upstreamliquid flow and a controlled quantity of metal ions can be introduced into the liquid plus gas solution flowing through the chamber. This can beused to deliver an example gas such as steam, which is considered to beparticularly effective for the hospital environment application.

Yet a further alternative embodiment is contemplated. A stepper motor orother device may be used to move the piston mechanically, and/or inresponse to a control signal provided by suitable control circuitry. Forexample, where the fluid flow is low, or is not considered suitable tomove the piston against the action of a spring (as is described abovewith reference to the figures), this embodiment may be used to bias ordisplace the piston to a position which will enable the passage of apredetermined amount of fluid through the chamber. The electrodes mayalso or in the alternative be displaced or biased toward each other.Also, the electrodes can be activated in a manner consistent with thenature of the fluid and the rate of flow of the fluid. For example, thestepper motor control may be determined in accordance with a look-uptable which specifies the type of fluid, the required electrode biasing,and the biasing of the piston. For example where it is desired to pass agas/fluid of low pressure through the chamber, the piston may be biaseda predetermined amount, the electrode(s) activated according to thedesired ion discharge required, and the piston moved to a predeterminedposition consistent with that particular type of gas/fluid.

The present invention may be used in a number of applications, such as:

-   domestic/home—for use in home, such as for producing drinking water;-   recreation—for use in recreation activities, such as for use in spas    and pools;-   commercial—for use in offices, such as controlling heterotropic    bacteria;-   building—for use in cooling towers, such as by reducing or    eliminating Legionella bacteria and reduce use of harsh chemicals;-   bulk water treatment—for use in treating water for re-use;-   industrial—for use in providing water with substantially little if    any bacteria;-   dental—for use in dealing with biofilm.-   Food industry—for washing fruit and vegetables.-   Marine industry—treatment of ships ballasts. Normally, within the    hull of a marine vessel there is an ideal environment for bacteria    growth given the supply of Fe oxide and oxygen. After treatment with    the present invention a ship May be able to dump its ballast in or    near port waters where otherwise the levels of organically harmful    material would have prevented a ship form doing this.-   Medical—cleaning and washing of hospital atmosphere and environment-   General industry—measuring and detecting fluid flow in domestic,    commercial and industrial environments.-   Application in the medical field has been generally noted above.    However, it has been shown that a particularly advantageous    application in the medical field is the introduction of silver ions    into a flow of water for disinfecting hospital environments by    destroying harmful bacteria that may reside in the atmosphere and on    hospital room surfaces and equipment, for example, oxygen masks.    Typical bacteria shown to have been successfully treated comprise    most widely known bacteria that thrive in the hospital environment    including staphylococcal or “golden staph”. To achieve this, water    may be passed through the apparatus of the present invention to    produce silver colloids as a resultant output of the electrolytic    cell of the apparatus. This colloid solution containing the    disinfecting silver in controlled amounts may then be atomized and    introduced into the hospital environment, for example through an air    conditioning system. Equally, as previously described herein, steam    may be used under controlled introduction of colloidal silver.    Introducing the disinfecting silver under such higher temperature    conditions has been shown to be particularly effective.

The present invention may provide a number of advantages, including:

-   fluid treatment is substantially proportional to fluid flow rate;-   where silver electrodes are used, the controlled introduction of    ions is such that only the desired amount (and therefore, form) of    silver ions is produced, thus without excess silver ions present,    the silver may not readily form salts, moreover, the silver, in its    colloidal form is not readily absorbed by humans or animals;-   where silver electrodes are used, the present invention has been    found effective in substantially removing and substantially    preventing formation of bio-film;-   treated fluid can go on to treat other fluid (second generation    treatment);-   where silver electrodes are used, dangerous compounds are not formed    when organic material ‘rots’. Ordinarily, under these conditions,    organic acids from the rotting material combine with chlorine    derived from water treated with prior art methods such as    chlorination, and produce trihalomethanes THM's. These compounds are    known carcinogens and have been banned where possible under    regulation. Thus, it would be particularly advantageous to replace    chlorination as a treatment for water;-   where silver electrodes are used, treated fluid reduces leaching of    organochloride compounds from PVC pipes;-   where silver electrodes are used, silver can replace chlorine;-   where silver is used, the treated fluid may also catalyse and carry    O⁻ (nascent oxygen having beneficial health and environmental    effects) produced from, say, H₂O₂ and remain stable in the fluid    bonded to the silver.

While this invention has been described in connection with specificembodiments thereof, it will be understood that it is capable of furthermodification(s). This application is intended to cover any variationsuses or adaptations of the invention following in general, theprinciples of the invention and including such departures from thepresent disclosure as come within known or customary practice within theart to which the invention pertains and as may be applied to theessential features hereinbefore set forth.

As the present invention may be embodied in several forms withoutdeparting from the spirit of the essential characteristics of theinvention, it should be understood that the above described embodimentsare not to limit the present invention unless otherwise specified, butrather should be construed broadly within the spirit and scope of thepresent invention as defined in the appended claims. Variousmodifications and equivalent arrangements are intended to be includedwithin the spirit and scope of the present invention and appendedclaims. For example, the body defining the fluid flow passage within theapparatus of the present invention is described in one embodiment hereinas a chamber. Equally, the body may be an open channel defining a fluidflow passage. Such variations to the body may be more suitable than aclosed channel arrangement depending on, for instance, the fluid beingprocessed. As a further example, the biasing means should notnecessarily be restricted to a coil spring as described in oneembodiment herein. It would be recognised by the person skilled in theart that other biasing means provide the equivalent function and may beused as a substitute.

Therefore, the specific embodiments are to be understood to beillustrative of the many ways in which the principles of the presentinvention may be practiced. In the following claims, means-plus-functionclauses are intended to cover structures as performing the definedfunction and not only structural equivalents, but also equivalentstructures. For example, although a nail and a screw may not bestructural equivalents in that a nail employs a cylindrical surface tosecure wooden parts together, whereas a screw employs a helical surfaceto secure wooden parts together, in the environment of fastening woodenparts, a nail and a screw are equivalent structures.

“Comprises/comprising” when used in this specification is taken tospecify the presence of stated features, integers, steps or componentsbut does not preclude the presence or addition of one or more otherfeatures, integers, steps, components or groups thereof.”

1. Apparatus for processing fluid comprising: a body defining a fluidflow passage having a fluid inlet and a fluid outlet, the bodycomprising a first electrode arrangement and a second electrodearrangement displaceable with respect to the first electrodearrangement, the first and second electrode arrangements adapted forconnection to a supply of electric current such that fluid within thebody forms part of an electrolytic cell providing for a flow of ionsbetween the first and second electrode arrangements; biasing meansoperatively associated with the second electrode arrangement and adaptedto displace the second electrode arrangement against a flow of fluidwithin the body in order to displace the second electrode arrangementinto closer proximity with the first electrode arrangement as the fluidflow rate increases, thereby increasing the flow of ions, and todisplace the second electrode arrangement away from the first electrodearrangement as the fluid flow rate decreases, thereby decreasing theflow of ions.
 2. Apparatus as claimed in claim 1, wherein the firstelectrode arrangement comprises an electrode fixed relative to the bodyand the second electrode arrangement comprises two opposed electrodes,mounted within a moveable support, allowing for positioning of the fixedelectrode therebetween.
 3. Apparatus as claimed in claim 1 or 2 wherein,the biasing means comprises a spring connected to the body means. 4.Apparatus as claimed in claim 1, 2 or 3, wherein the ions are metal ionshaving anti-microbial and plating out properties such that the metalions plate to fluid contact surfaces of the body and fluid carrier meanslocated beyond the body to form a biostatic film on the fluid contactsurfaces.
 5. Apparatus as claimed in claim 2, 3 or 4, wherein themoveable support comprises a piston and at least one of the electrodearrangements comprises silver for producing a flow of silver ionsbetween the electrodes.
 6. Apparatus as claimed in any one of claims 1to 6 further comprising an electric circuit for supplying electriccurrent to the electrolytic cell.
 7. Apparatus as claimed in claim 6further comprising: fluid flow measurement means for determining whetherthere is actual fluid flow between the inlet and the outlet of the body,and wherein; the electric circuit for supplying electric current to theelectrolytic cell comprises circuit control means for reducing theelectric current supplied to the first and second electrode arrangementsif there is no actual fluid flow determined by the fluid flowmeasurement means.
 8. Apparatus as claimed in claim 7, wherein the fluidflow measurement means comprises a flow switch having a magnet and areed switch.
 9. Apparatus as claimed in claim 8, wherein the electriccircuit comprises circuitry for activating a standby mode comprising: anoperational amplifier circuit in a current return path of the electriccircuit adapted to detect a no fluid flow current threshold levelselected to be nominally greater than a galvanic current drawn by theelectrolytic cell when there is no fluid flow in the body, theoperational amplifier circuit further adapted to output a signalindicating a no fluid flow condition upon detecting the no fluid flowcurrent threshold level; a micro-controller adapted to receive outputsignals of the operational amplifier and, upon receiving an outputsignal indicating the no fluid flow condition, increment a timer withinthe micro-controller for a predetermined continuous period of time atthe end of which, if the no fluid flow condition remains, themicro-controller is further adapted to activate the standby mode byactivating a circuit shunt means within the electric circuit to reducethe electric current supplied to the first and second electrodearrangements.
 10. Apparatus as claimed in claim 9, wherein the electriccircuit further comprises circuitry for activating an operating modecomprising: the operational amplifier circuit adapted to detect a fluidflow current threshold level selected to be nominally greater than theno fluid flow current threshold level, the operational amplifier circuitfurther adapted to output a signal indicating a fluid flaw conditionupon detecting the fluid flow current threshold level; sampling meansfor periodically sampling the output of the operational amplifiercircuit at the micro-controller during the standby mode; circuit meansfor increasing an electric current supply to the first and secondelectrode arrangements in response to the micro-controller receiving asampled output signal from the operational amplifier circuit indicatingthe fluid flow condition.
 11. A method of processing a fluid comprisingthe steps of: providing a body defining a fluid flow passage having afluid inlet and a fluid outlet, the body comprising a first electrodearrangement and a second electrode arrangement displaceable with respectto the first electrode arrangement, the first and second electrodearrangements adapted for connection to a supply of electric current suchthat fluid within the body forms part of an electrolytic cell providingfor a flow of ions between the first and second electrode arrangements;providing an electric current supply from an electric circuit to thefirst and second electrode arrangements; passing the fluid through thebody such that the displacement of the second electrode arrangement isbiased against the flow of fluid within the body in order to displacethe second electrode arrangement into closer proximity with the firstelectrode arrangement as the fluid flow rate increases, therebyincreasing the flow of ions, and to displace the second electrodearrangement away from the first electrode arrangement as the fluid flowrate decreases, thereby decreasing the flow of ions.
 12. A method asclaimed in claim 11, further comprising the steps of: determiningwhether there is actual fluid flow between the inlet and the outlet ofthe body, and; reducing the electric current supplied to the first andsecond electrode arrangements if there is no actual fluid flowdetermined in the actual fluid flow determining step.
 13. A method asclaimed in claim 12, wherein the actual fluid flow determining stepcomprises the use of a flow switch and wherein the flow switch comprisesa magnet and a reed switch.
 14. A method as claimed in claim 11, furthercomprising activating a standby mode comprising the steps of:determining a no fluid flow condition by adapting an operationalamplifier circuit in a current return path of the electric circuit todetect a no fluid flow current threshold level selected to be nominallygreater than a galvanic current drawn by the electrolytic cell whenthere is no fluid flow in the body; providing an output signal of theoperational amplifier circuit to a micro-controller; upon receiving anoutput signal of the operational amplifier circuit indicating the nofluid flow condition, incrementing a timer within the micro-controllerfor a predetermined continuous period of time at the end of which, ifthe no fluid flow condition remains, the micro-controller activates thestandby mode by activating a circuit shunt means within the electriccircuit to reduce the electric current supplied to the first and secondelectrode arrangements.
 15. A method as claimed in claim 14, furthercomprising activating an operating mode comprising the steps of:determining a fluid flow condition by adapting the operational amplifiercircuit to detect a fluid flow current threshold level selected to benominally greater than the no fluid flow current threshold; periodicallysampling the output of the operational amplifier circuit at themicro-controller during the standby mode; upon receiving an outputsignal of the operational amplifier circuit indicating the fluid flowcondition, the micro-controller deactivates the circuit shunt means toresume the electric current supplied to the first and second electrodearrangements.
 16. A method as claimed in any one of claims 11 to 15,wherein the ions are metal ions having anti-microbial and plating outproperties such that the metal ions plate to fluid contact surfaces ofthe body and fluid carrier means located beyond the body to form abiostatic film on the fluid contact surfaces.
 17. A method as claimed inany one of claims 11 to 16, wherein at least one of the first and secondelectrode arrangements comprises silver for producing a flow of silverions between the first and second electrode arrangements.
 18. A methodof determining fluid flow comprising the steps of: providing a bodydefining a fluid flow passage having a fluid inlet and a fluid outlet,the body comprising a first electrode arrangement and a second electrodearrangement displaceable with respect to the first electrodearrangement, the first and second electrode arrangements adapted forconnection to a supply of electric current such that fluid within thebody forms part of an electrolytic cell providing for a flow of ionsbetween the first and second electrode arrangements; providing anelectric current supply from an electric circuit to the first and secondelectrode arrangements; passing the fluid through the body such that thedisplacement of the second electrode arrangement is biased against aflow of fluid within the body in order to displace the second electrodearrangement into closer proximity with the first electrode arrangementas the fluid flow rate increases, thereby increasing the flow of ions,and to displace the second electrode arrangement away from the firstelectrode arrangement as the fluid flow rate decreases, therebydecreasing the flow of ions; determining the fluid flow rate bymeasuring either one or both of: an ion current density between thefirst and second electrode arrangements, and; a relative displacement ofthe first and second electrode arrangement.
 19. A method as claimed inclaim 18, wherein: the step of providing an electric current supplycomprises supplying an electric current regulated by a micro-controllerwithin the electric circuit, and; the step of measuring an ion currentdensity comprises detecting a current sense signal, corresponding to theion current density, in a current return path of the electric circuit.20. A method as claimed in claim 19, further comprising the step ofactivating a standby mode comprising the steps of: determining a nofluid flow condition by adapting an operational amplifier circuit in thecurrent return path of the electric circuit to detect a no fluid flowcurrent threshold level selected to be nominally greater than thegalvanic current drawn by the electrolytic cell when there is no fluidflow in the body; providing an output signal of the operationalamplifier circuit to the micro-controller; upon receiving an outputsignal of the operational amplifier circuit indicating the no fluid flowcondition, incrementing a timer within the micro-controller for apredetermined continuous period of time at the end of which, if the nofluid flow condition remains, the micro-controller activates the standbymode by activating circuit shunt means to reduce the electric currentsupplied to the first and second electrode arrangements.
 21. A method asclaimed in claim 20, further comprising the step of activating anoperating mode comprising the steps of: determining a fluid flowcondition by adapting the operational amplifier circuit to detect afluid flow current threshold level selected to be nominally greater thanthe no fluid flow current threshold; periodically sampling the output ofthe operational amplifier circuit at the micro-controller during thestandby mode; upon receiving an output signal of the operationalamplifier circuit indicating the fluid flow condition, themicro-controller deactivates the circuit shunt means to resume theelectric current supplied to the first and second electrodearrangements.
 22. A method as claimed in any one of claims 11 to 17 or,18 to 21 further comprising the step of: providing a display to indicatethe activation of the standby mode and/or the activation of theoperating mode.
 23. Biasing means adapted for controlled operation bythe passage of fluid in a fluid passage, the biasing means beingoperative to displace a first electrode relative to a second electrode,the biasing means comprising: a displacement means for displacing thefirst electrode toward the second electrode proportional to an increasein the rate of flow of fluid in the passage.
 24. A biasing means asclaimed in claim 23, wherein the displacement of the first electrodetoward the second electrode provides an increase in ion flow or ioncurrent density between the electrodes.
 25. A biasing means as claimedin claim 23 or 24, wherein there is a substantially proportionalrelationship between fluid flow rate and ion flow or ion current densitybetween the electrodes.
 26. A biasing means as claimed in claim 23, 24or 25, wherein there is a substantially proportional relationshipbetween fluid flow rate and displacement of the first electrode relativeto the second electrode.
 27. A biasing means as claimed in claim 25 or26, wherein the proportional relationship is substantially a directlyproportional relationship.
 28. Trigger means operably associated with abiasing means as claimed in any one of claims 23 to 27, the triggermeans comprising: a first switch means disposed in association with thedisplacement means, a second switch means adapted to cooperate with thefirst switch means, in a first position, to form a trigger.
 29. Triggermeans operably associated with an apparatus as claimed in any one ofclaims 1 to 10, the trigger means comprising: a first switch meansdisposed in association with the second electrode arrangement, a secondswitch means adapted to cooperate with the first switch means, in afirst position, to form a trigger.
 30. A trigger means as claimed inclaim 28 or 29, wherein the second switch means is moveable relative tothe first switch means.
 31. A trigger as claimed in claim 30, whereinthe second switch means is releasably fixed relative to the first switchmeans.
 32. A trigger as claimed in any one of claims 28 to 31, whereinthe first switch means is a magnet.
 33. A trigger as claimed in any oneof claims 28 to 32, wherein the second switch means is a reed switch.34. A method substantially as herein described with reference to atleast one of the accompanying drawings.
 35. An apparatus substantiallyas herein described with reference to at least one of the accompanyingdrawings.